Bicycle frame and drive link case therefore

ABSTRACT

A bicycle frame includes a front section and a rear section. The front section includes a front frame portion having a front coupling configured to receive a front wheel support member and to allow rotation between the front coupling and the front wheel support member, the front frame portion defining a central vertical plane of the frame. The rear section includes a drive link case having an upper tube, a lower tube, a rear hub housing, and a front sprocket housing all integrally arranged with each other to form a rigid drive link case having an opening disposed between the upper and lower tubes, the drive link case being connected to the front frame portion via the front sprocket housing. The drive link case is disposed eccentric to the central vertical plane and is cantilevered rearward from the front sprocket housing. The front frame portion extends forward from the front sprocket housing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 60/968,232, filed Aug. 27, 2007, which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

The present disclosure relates generally to a bicycle frame, andparticularly to features of a bicycle frame, such as the structural rearsection of the bicycle frame, and a foldable bicycle frame.

BRIEF DESCRIPTION OF THE INVENTION

An embodiment of the invention includes a bicycle frame configured toreceive front and rear wheels. The frame includes a front section and arear section. The front section includes a front frame portion having afront coupling configured and dimensioned to receive a front wheelsupport member and to allow a rotational degree of freedom between thefront coupling and the front wheel support member, the front frameportion defining a central vertical plane of the frame. The rear sectionincludes a drive link case, the drive link case having an upper tube, alower tube, a rear hub housing, and a front sprocket housing allintegrally arranged with each other to form a rigid drive link casehaving an opening disposed between the upper and lower tubes, the drivelink case being connected to the front frame portion via the frontsprocket housing. The drive link case is disposed eccentric to thecentral vertical plane and is cantilevered rearward from the frontsprocket housing. The front frame portion extends forward from the frontsprocket housing.

Another embodiment of the invention includes a drive link case for abicycle frame having an upper tube, a lower tube, a rear hub housing,and a front sprocket housing all integrally arranged with each other toform a rigid drive link case having an opening disposed between theupper and lower tubes. The upper and lower tubes are disposednon-parallel to each other. At least one of the upper tube and the lowertube has a cross-sectional height that is greater than a respectivecross-sectional width. Material forming the upper tube is non-separablealong its respective length and around its respective circumference,material forming the lower tube is non-separable along its respectivelength and around its respective circumference; material forming therear hub housing is non-separable with the material forming the uppertube and the material forming the lower tube; and material forming thefront sprocket housing is non-separable with the material forming theupper tube and the material forming the lower tube.

Another embodiment of the invention includes a bicycle frame configuredto receive front and rear wheels. The frame includes a front section anda rear section. The front section includes a front coupling configuredand dimensioned to receive a front wheel support member and to allow arotational degree of freedom between the front coupling and the frontwheel support member, the front section defining a central verticalplane of the frame. The rear section includes a drive link case, thedrive link case comprising an upper tube, a lower tube, a rear hubhousing, and a front sprocket housing all integrally arranged with eachother to form a rigid drive link case having a centrally disposed windowbetween the upper and lower tubes, the rear section being connected tothe front section via the front sprocket housing. The drive link case isdisposed eccentric to the central plane and being cantilevered rearwardfrom the front sprocket housing, the front section extending forwardfrom the front sprocket housing.

Another embodiment of the invention has the rear section rigidlyconnected to the front section.

Another embodiment of the invention has the rear section pivotallyconnected to the front section about an axis substantially normal to thevertical plane of the frame.

Another embodiment of the invention has the drive link case pivotallyconnected to the front section as in the form of a swing arm to allowsuspension therebetween.

Another embodiment of the invention further includes means forsuspension between the front section and the rear section.

Another embodiment of the invention includes a shock absorber with themeans for suspension.

Another embodiment of the invention further includes a seat supportfixedly attached to at least one of the front section and the rearsection.

Another embodiment of the invention has the seat support fixedlyattached to the front section.

Another embodiment of the invention has the rear hub housing of thedrive link case configured and dimensioned to secure to and to form anenclosure over an exposed end of a bicycle torque converter assemblyconfigured to transmit torque from a drive link to a rear wheel, wherethe drive link receives an input torque from a front sprocket within thefront sprocket housing.

Another embodiment of the invention has for the drive link a bicycledrive chain.

Another embodiment of the invention has the drive link case configuredand dimensioned to receive a bicycle drive chain disposed in a looptraversing a path extending from the front sprocket housing, through theupper tube, around the interior of the rear hub housing, through thelower tube, and returning to the front sprocket housing.

Another embodiment of the invention has the drive link case completelyenclosing the bicycle chain.

Another embodiment of the invention has the bicycle torque converterincluding a set of gears having a plurality of gear ratios.

Another embodiment of the invention has for the bicycle torque convertera multi-speed internally geared hub.

Another embodiment of the invention has the rear hub housing includingsupports for supporting the axis of the torque converter assembly andfor supporting torque reaction loads between the rear hub housing andthe torque converter assembly.

Another embodiment of the invention has the drive link case including achain tensioner support.

Another embodiment of the invention further includes means fortensioning the drive link.

Another embodiment of the invention has the front coupling furtherconfigured and dimensioned to receive a one-sided front wheel supportmember disposed eccentric to the central plane and disposed on the sameside of the front section as the eccentrically disposed drive link case.

Another embodiment of the invention has the front sprocket housingcloser to the central plane than is the rear hub housing therebydefining the drive link case to have an offset shape.

Another embodiment of the invention has at least one of the upper tubeand the lower tube with a faceted tubular cross section.

Another embodiment of the invention has the drive link case furtherincluding an access window configured and sized to receive a hub gearshift cable.

Another embodiment of the invention has the rear hub housing including aremovable cover to provide access to the interior of the rear hubhousing.

Another embodiment of the invention has the front sprocket housingconfigured and dimensioned to receive an eccentric crank, the frontsprocket housing further including an eccentric disc crank cover that isrotatable and removable to provide for installation of and alignmentwith the eccentric crank.

Another embodiment of the invention has the drive link case includingmeans for mounting a disc brake caliper.

Another embodiment of the invention has the upper and lower tubes of thedrive link case non-parallel to each other.

Another embodiment of the invention further includes a frame hingedisposed between the front section and the rear section, the frame hingeincluding means for: rigidly fixing the front section to the rearsection such that the front and rear wheels are lockable in line witheach other suitable for riding; pivotally displacing the front sectionwith respect to the rear section such that the front and rear wheels arenot in line with each other; and, holding via a detent the front sectionand rear section together in a pivotally displaced condition suitablefor storage.

Another embodiment of the invention further includes a frame hinge, theframe hinge including an upper portion and a lower portion, each of theupper and lower portions having at least two interlocking features suchthat the interlocking features of the upper portion engage with theinterlocking features of the lower portion, and a fastener or clampingmechanism disposed to rigidly fasten the upper portion to the lowerportion. Wherein the interlocking features and the fastener or clampingmechanism provide for rigid fixation of the upper portion to the lowerportion with the front and rear wheels disposed in line with each other.

Another embodiment of the invention is configured such that in responseto the interlocking features of the upper portion and the interlockingfeatures of the lower portion being engaged with each other, and inresponse to the fastener or clamping mechanism fastening the upperportion to the lower portion, the upper and lower portions of the framehinge are prevented from having any relative movement between them, andin response to the fastener or clamping mechanism being loosened and notfastening the upper portion to the lower portion, the upper and lowerportions of the frame hinge are prevented from having rotationalrelative movement between them until the upper and lower portions arepartially separated from each other via translational relative movementbetween them.

Another embodiment of the invention is configured such that in responseto the upper and lower portions being only partially separated from eachother, a first of the interlocking features of the upper portion and afirst of the interlocking features of the lower portion remain engagedwith each other and act as a pivot, and a second of the interlockingfeatures of the upper portion and a second of the interlocking featuresof the lower portion are disengaged from each other thereby allowing theupper portion to pivot on the lower portion about the pivot defined bythe pair of first interlocking features.

Another embodiment of the invention has the first interlocking featureof the upper portion and the first interlocking feature of the lowerportion each including a pass-through hole providing a through passageat the pivot from one side of the hinge to the other side for passage ofcables therethrough.

Another embodiment of the invention has the front section including twoparallel tubes extending substantially upward from the front sprockethousing of the drive link case, thereby defining a first portion of thefront section, and then extending substantially forward toward the frontcoupling, thereby defining a second portion of the front section.

Another embodiment of the invention further including a rotatable jointdisposed in the first portion of the front section and having a pivotaxis in a near-vertical orientation, the rotatable joint including aclamping mechanism that rigidly clamps the first portion to the secondportion in the central vertical plane in a manner to make the bicycleframe suitable for riding.

Another embodiment of the invention has the rotatable joint disposed inline with the rearward tube of the two parallel tubes of the firstportion, the rotatable joint including an axial through opening in linewith the opening of the rearward tube thereby providing a passage wayfor brake and shifting cables to run through the tubular first andsecond portions of the front section across the rotatable joint.

Another embodiment of the invention further includes a seat supportattached to the front section via a seat support clamp that permits theseat support to be disposed in a first position suitable for riding andin a second position suitable for storing.

Another embodiment of the invention has the drive link case including aremovable cover to provide access to the interior of the drive link casefor removing and replacing a drive link that cannot be split apart.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the exemplary drawings wherein like elements are numberedalike in the accompanying Figures:

FIG. 1 depicts in right side view an exemplary embodiment of a bicyclein accordance with an embodiment of the invention;

FIG. 2 depicts in left side view an alternative embodiment of a bicyclein accordance with an embodiment of the invention;

FIG. 3 depicts in right side view the bicycle of FIG. 1 in a foldedposition;

FIG. 4 depicts in top plan view a drive link case in accordance with anembodiment of the invention;

FIG. 5 depicts in right side isometric view the drive link case of FIG.4;

FIG. 6 depicts in right side isometric view a cutaway portion of thedrive link case of FIGS. 4 and 5;

FIG. 7 depicts in cross sectional view a torque converter assembly foruse in accordance with an embodiment of the invention;

FIGS. 8 and 9 depict in right side isometric view interface featuresbetween the drive link case and the torque converter assembly inaccordance with an embodiment of the invention;

FIG. 10 depicts in left side view the drive link case providing meansfor tensioning a drive link, such as a bicycle chain, in accordance withan embodiment of the invention;

FIG. 11 depicts in right side view a pivotally arranged drive link casein accordance with an embodiment of the invention;

FIG. 12 depicts in left side view the pivotally arranged drive link caseof FIG. 11;

FIGS. 13A, B and C depict in right side view an exemplary frame hinge,also herein referred to as a clamping mechanism or a rotatable joint, inaccordance with an embodiment of the invention, where FIG. 13B is adetailed section view of a portion of FIG. 13A, and FIG. 13C is anexpanded view of a portion of FIG. 13B;

FIG. 14 depicts in right side view the drive link case of FIG. 6 withoptional features in accordance with an embodiment of the invention;

FIG. 15 depicts in right side view the drive link case of FIGS. 5 and 6with an alternative arrangement for a brake caliper in accordance withan embodiment of the invention;

FIGS. 16-18 depict right side view, right side view, left side view, andtop plan view, respectively, of a bicycle or portions thereof inaccordance with an embodiment of the invention;

FIG. 19 depicts in right side view an alternative drive link case tothat depicted in FIG. 14 in accordance with an embodiment of theinvention; and

FIG. 20 depicts in right side isometric view an exemplary drive link foruse in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the invention, as shown and described by the variousfigures and accompanying text, provides a bicycle frame having one orboth of the following features: a rear chain case that serves as astructural member to support the rear bicycle wheel absent the need fora triangular rear section typical of bicycle frames employing twotriangular frame sections; and/or, a hinge having a pivot axis in anear-vertical orientation to allow the bicycle frame to be foldedsubstantially in half, front-wheel-to-rear-wheel. While embodimentsdescribed herein depict or imply a bicycle chain as a drive link (seedrive link 385 in FIG. 21 for example) to transfer drive torque from afront crank sprocket to a rear wheel sprocket, it will be appreciatedthat the disclosed invention is also applicable to other drive linkssuitable for the purposes disclosed herein.

FIG. 1 is an exemplary embodiment (right side view) of a bicycle 100having a bicycle frame 105 configured to receive front 110 and rear 115wheels. The frame includes a front section 120 and a rear section 125.The front section 120 includes a front coupling 130 configured anddimensioned to receive a front wheel support member 135 and to allow arotational degree of freedom between the front coupling 130 and thefront wheel support member 135, the front section 120 defining a centralvertical plane of the frame 105. The rear section 125 includes a drivelink case 140 having an upper tube 145, a lower tube 150, a rear hubhousing 155, and a front sprocket housing 160, all integrally arrangedwith each other to form a rigid drive link case 140 having a centrallydisposed open window 165 between the upper and lower tubes 145, 150. Therear section 125 is connected to the front section 120 via the frontsprocket housing 160. The drive link case 140 is cantilevered rearwardfrom the front sprocket housing 160, and the front section 120 extendsforward from the front sprocket housing 160. A seat support 170 isfixedly attached to at least one of the front section 120 and the rearsection 125, the seat support 170 having an upper support 171 and alower support 172 with a opening 173 disposed therebetween. As depictedin FIG. 1, the seat support 170 is fixedly attached to the front section120. A further feature of an embodiment of bicycle frame 105 is a hinge175 for folding the bicycle frame in half, in afront-wheel-to-rear-wheel arrangement.

While additional details of the bicycle frame 105 will be describedfurther below, reference is now briefly made to embodiments depicted inFIGS. 2 and 3. FIG. 2 depicts a bicycle 100 (left side view) similar tothat of FIG. 1, but with an alternative arrangement for the seat support170. FIG. 3 depicts the bicycle 100 (right side view) of FIG. 1 in afolded position by folding the bicycle frame 105 about hinge 175 suchthat the front wheel 110 is disposed in substantial axial alignment withthe rear wheel 115.

Referring now to FIG. 4 (top plan view), the drive link case 140 in anembodiment is disposed eccentric to the central vertical plane 180 ofthe frame 105, thereby serving to define a one-sided frame 105. Anotherfeature that serves to define the one-sided frame 105 is the frontcoupling 130, which is configured and dimensioned to receive a one-sidedfront wheel support member 135 disposed eccentric to the centralvertical plane 180 and disposed on the same side of the front section120 as the eccentrically disposed drive link case 140 (best seen byreferring to FIG. 16 in association with FIG. 1, where referencenumerals 105′ and 120′ of FIG. 16 refer respectively to referencenumerals 105 and 102 of FIG. 1, but in the alternative).

In an embodiment, the front sprocket housing 160 is disposed closer tothe central plane 180 than is the rear hub housing 155 (that is,distance “d1” is less than distance “d2”), thereby defining the drivelink case 140 to have an offset shape, or an s-shape (illustrated byoffset dashed center line 142 and offset distance “d3”). An offset drivelink case places the front sprocket housing 160 closer to the centralvertical plane 180 for improved rider comfort, while positioning therear hub housing 155 a suitable distance away from the central verticalplane 180 and rear wheel 115 serves to accommodate a suitably sizedtorque converter assembly (discussed in more detail below) for purposesdisclosed herein.

Referring now to FIG. 5 (right side isometric view), the rear hubhousing 155 of the drive link case 140 is configured and dimensioned tosecure to and to form an enclosure over an exposed end of a bicycletorque converter assembly 185 (details seen in FIG. 7 discussed furtherbelow) configured to transmit torque from a drive link, such as abicycle drive chain, to the rear wheel 115, where the drive linkreceives an input torque from a front sprocket (390 in FIG. 21 forexample) within the front sprocket housing 160.

Referring to FIGS. 5 and 6 together, the upper tube 145 and lower tube150 of drive link case 140 are not parallel with each other and havefaceted tubular cross sections that form part of a continuous throughpassage extending from the front sprocket housing 160, through the uppertube 145, around the interior of the rear hub housing 155, through thelower tube 150, and returning to the front sprocket housing 160, therebyproviding a drive link case 140 that is configured and dimensioned toreceive a bicycle drive chain disposed in a loop traversing a pathwithin the above-mentioned continuous through passage. In an embodiment,the drive link case 140 completely encloses the bicycle chain within thetubular through passage and housings 155, 160. While embodimentsdepicted and described herein illustrate a faceted tubular cross sectionfor upper and lower tubes 145, 150 having eight facets (planarsurfaces), it will be appreciated that the scope of the invention is notso limited and extends to any other number of facets, but preferably isof a number greater than four.

In an embodiment, at least one of the upper tube 145 and the lower tube150 has an overall cross-sectional height “h” that is greater that arespective overall cross-sectional width “w”, which serves to improvethe stiffness-to-weight ratio of the drive link case 140.

In an embodiment, material forming the upper tube 145 is continuousand/or non-separable along its respective length and around itsrespective circumference, material forming the lower tube 150 iscontinuous and/or non-separable along its respective length and aroundits respective circumference, material forming the rear hub housing 155is continuous and/or non-separable with the material forming the uppertube 145 and the material forming the lower tube 150, and materialforming the front sprocket housing 160 is continuous and/ornon-separable with the material forming the upper tube 145 and thematerial forming the lower tube 150. Manufacturing methods such asbladder molding are well suited for producing the above-described drivelink case 140 with continuous and/or non-separable material flow,thereby enabling production of a one-piece structure having a highstrength-to-weight ratio with efficient use of material, and without theneed for clamping bolts (sideways clamping bolts used to clamp twohalves of a clam shell arrangement for example) that tend to introduceundesirable stress concentrations at the bolt locations. In addition,absence of a separable joint along the length of the upper and lowertubes 145, 150 provides for predictable stress distributions along therespective lengths, with the upper tube 145 experiencing greatercompression than the lower tube 150 when the drive link is in tension,thereby allowing for the dimensions and configurations of the upper andlower tubes to be independently optimized for the expected levels ofworking stress.

A one-piece drive link case 140 having upper and lower tubes 145, 150with a centrally disposed window 165 provides for an improved torsionalstiffness-to-weight ratio by placing structural material of the upperand lower tubes 145, 150 a defined distance away from a central axisdefined by a line connecting the center of the rear hub housing 155 withthe center of the front sprocket housing 160.

An embodiment of the torque converter assembly 185 partially depicted inFIG. 5 will now be described with reference to FIG. 7 (cross sectionalview) and FIGS. 8 and 9 (right side partial isometric view). The rearhub housing 155 of torque converter assembly 185 encloses a set of gears(illustrated generally by reference numeral 190) having a plurality ofgear ratios, thereby providing a multi-speed internally geared hub.While FIG. 7 illustrates a certain volume allocated for an arrangementof gears 190, it will be appreciated that the scope of the invention isnot so limited and also encompasses other arrangements of gears that areso configured and dimensioned to work in conjunction with a type ofbicycle herein disclosed, and especially in conjunction with a type ofdrive link case 140 herein disclosed. An example of a set of gears 190in a multi-speed hub that can be shifted from one side of the rear axleis illustrated in U.S. Pat. No. 4,721,013, issued Jan. 26, 1988. Anotherexample of a set of gears 190 in a multi-speed hub is illustrated athttp://www.sram-imotion.com/de/html/navigation_de.html. The rear hubhousing 155 is supported from the drive link case 140 via a cartridgebearing 200 that is axially restrained via a retaining clip (such as acirclip, a c-clip, an e-clip, for example) (not shown but well known inthe art). The axis 195 of the torque converter assembly 185 has asquared off end 205 that is supported by the rear hub housing 155 viasquare support 210 formed on the interior of a hub cover 215 (depictedin FIGS. 8 and 9), thereby supporting torque reaction loads between therear hub housing 155 and the torque converter assembly 185. It should benoted that the torque support (ends 205 in support 210) is absent anaxial load transferred to the axle of the bicycle, that is, the bicycleaxle is axially free to slide. As also depicted in FIGS. 8 and 9, and asbriefly mentioned above, the rear hub housing 155 includes removablecover 215 to provide access to the interior of the rear hub housing 155.Bolts 235 secure the hub cover 215 to the body of the rear hub housing155 of the drive link case 140.

While reference is made herein to “squared off” end 205 and “square”support 210, it will be appreciated that the scope of the invention isnot limited to a “square” geometry and extends to other geometriessuitable for the purposes disclosed herein, such as octagonal forexample.

While the description herein and the illustration of the various figuresdescribe and show a hub cover 215 that provides only partial access tothe interior of drive link case 140 at the rear hub housing 155, analternative arrangement may have the entire outer half of drive linkcase 140 removable.

Referring briefly back to FIG. 6, the drive link case 140 also includesan access window 225 configured and sized to receive a hub gear shiftcable 230 for operating the multi-speed internally geared hub discussedabove.

Referring now to FIG. 10 (left side view), an embodiment includes ameans for tensioning the drive link via the crank 240 used to pedal thebicycle. Here, the means for tensioning is provided by an eccentriccrank 240, which is arranged on drive link case 140 so that the crankpivot 245 is capable of traversing a circular path about the center ofthe front sprocket housing 160, thereby causing the front drive sprocketto have eccentric rotation, which in turn tensions the drive link as thecrank pivot 245 rotates forward. In an embodiment, the eccentric crank240 is formed having an internal cylindrical bearing that has an offsetcore (the core being concentric with crank pivot 245 and thereforegenerally referred to by reference numeral 245). The front sprockethousing 160 includes an eccentric disc crank cover 250 that is rotatableand removable to provide for installation of and alignment with theeccentric crank 240. An eccentric bottom bracket 375 may be loosened andtightened by bolt 380, which bolts into the frame 105 of the bicycle 100when the eccentric crank 240 and bottom bracket 375 have been rotated toproperly tension the drive link. Once locked in position with the drivelink properly tensioned, crank pivot 245 is fixed and crank 240 pivotsabout crank pivot 245. An embodiment of such an eccentric crank andbottom bracket is disclosed in commonly owned U.S. Pat. No. 7,217,037,issued May 15, 2007, which is herein incorporated by reference in itsentirety.

In an embodiment, the drive link case 140 is rigidly connected to thefront section 120 via the front sprocket housing (via welds, bolts orother suitable fastening means), as depicted generally in FIGS. 1 and 2,thereby resulting in a rigid frame 105 from front section 120 to rearsection 125. However, in another embodiment, and with reference now toFIGS. 11 and 12, the drive link case 140 is pivotally connected to thefront section 120 as in the form of a swing arm to allow suspensiontherebetween, thereby providing a means for suspension between the frontsection 120 and the rear section 125. As depicted in FIGS. 11 and 12, anembodiment of the means for suspension is a shock absorber 255 coupledbetween the drive link case 140 at a bottom end 260, and the frontsection 120 at a top end 265 (best seen by referring to FIG. 12). Acrank housing 270 provides an axis of rotation of drive link case 140that is substantially normal to the vertical plane (180, depicted inFIG. 4) of the frame 105.

Referring back to FIG. 1, an embodiment of the front section 120includes two parallel tubes 275 that extend substantially upward (moreupward than forward) from the front sprocket housing 160 of the drivelink case 140 to define a first portion 280 of the front section 120,and then extend substantially forward (more forward than upward) towardthe front coupling 130 to define a second portion 285 of the frontsection 120. A rotatable joint, also herein referred to as a hinge, 175is disposed in the first portion 280 of the front section 120 and has apivot axis 335 (best seen by reference to FIGS. 13A, B and C) in anear-vertical orientation. The rotatable joint includes a clampingmechanism 290 (best seen by referring to FIGS. 13A, B and C), thatrigidly clamps the first portion 280 in alignment with the secondportion 285 in the central vertical plane 180 in a manner to make thebicycle frame suitable for riding.

In an embodiment, the first portion 280 and second portion 285 areherein also collectively referred to as the front frame section(generally referred to by reciting reference numerals 280, 285 incombination). However, and with reference to FIG. 16, an alternativeembodiment employs a front frame section defined by a rigidsubstantially triangular form 395 having a top frame member 400, a downframe member 405, and a seat frame member 410, the top frame member 400extending from the front coupling 130 to an upper end of the seat framemember 410, and the down frame member 405 extending from the top framemember 400 at the front coupling 130 to a lower end of the seat framemember 410, thereby defining the rigid substantially triangular form.The drive link case 140 is connected to the front frame portion(generally referred to by reciting reference numerals 400, 405, 410 incombination) proximate the lower end of the seat frame member 410.

With reference now to FIGS. 13A, B and C (right side partial isometricview with varying levels of detail), the clamping mechanism 290, whichis more generally referred to as hinge 175, includes an upper portion295 and a lower portion 300, each of the upper 295 and lower 300portions having at least two interlocking features 305, 306 and 310,311, respectively, such that the interlocking features 305, 306 of theupper portion 295 engage with the interlocking features 310, 311 of thelower portion 300. For example, but without limitation, interlockingfeature 310 (left side of lower portion 300) is a long hollow tube thatengages with mating detail of interlocking feature 305 (left side ofupper portion 295), and interlocking feature 311 (right side of lowerportion 300) is a short hollow tube that engages with mating detail ofinterlocking feature 306 (right side of upper portion 295). When theinterlocking features 305, 306 and 310, 311 are aligned and engaged, afastener (or any other clamping mechanism suitable for the purposesdisclosed herein) 315 is so disposed to threadably engage with threadedboss 320 to rigidly fasten the upper portion 295 to the lower portion300 with the front 110 and rear 115 wheels disposed and locked in linewith each other. As depicted in FIG. 13A, tubes 275 associated withfirst portion 280 extend out of the bottom of lower portion 300, andtubes 275 associated with second portion 285 extend out of the top ofupper portion 295, thereby forming one continuous front section 120 offrame 105 when the upper 295 and lower 300 portions are rigidly coupled.While FIG. 13A depicts a bolt 315 with an internal hex head for rigidlyfastening upper and lower portions 295, 300 together, it will beappreciated that the invention is not so limited and also extends toother fasteners suitable for the purposes disclosed herein, such as abolt with a thumb wheel head or a quick release clamping mechanism, forexample. To facilitate rotation of the upper 295 and lower 300 portions,which will be discussed in more detail below, interlocking feature 310of lower portion 300 has a boss height “A”, interlocking feature 311 oflower portion has a boss height “B” that is less than height “A”, andthreaded boss 320 of lower portion 300 has a boss height “C” that isless than or equal to height “B”.

Continuing on with reference to FIGS. 13A, B and C, the rotatable joint,depicted generally by rotation line 325, of hinge 175 is formed byinterlocking features 305 and 310 being disposed in line with therearward tube (left side of FIG. 13A) of the two parallel tubes 275 ofthe first 280 and second 285 portions. The rotatable joint 325 includesan axial through opening 330 in line with the opening of the rearwardtube, thereby providing a passage way for brake and shifting cables torun through the tubular first 280 and second 285 portions of the frontsection 120 across the rotatable joint 325. Described alternatively, afirst interlocking feature 305 of the upper portion 295 and the firstinterlocking feature 310 of the lower portion 300 each include apass-through hole 330 providing a through passage at the pivot 325 fromone side of the hinge 175 (clamping mechanism 290) to the other side forpassage of cables therethrough.

As depicted in FIG. 13A, the pivot axis 335 is arranged in anear-vertical orientation even though the central axis 340 passingthrough tubes 275 is not in a near-vertical orientation. Describedalternatively, the central axis 340 passing through tubes 275 forms anangle α with respect to the pivot axis 335 that is greater than zerodegrees. As such, hinge 175 permits rotation of the front section 120relative the rear section 125 with the front 110 and rear 115 wheelsstaying substantially level with each other and with a horizontal plane(the ground).

Notwithstanding the foregoing, hinge 175 may be described alternativelyas being disposed in the first portion 280 such that: the front 110 andrear 115 wheels are lockable in line with each other suitable forriding; at least a portion of the front section 120 is pivotallydisplaceable with respect to the rear section 125 such that the front110 and rear 115 wheels are not in line with each other; and, at least aportion of the front section 120 and the rear section 125 arepositionally fixable together via a first detent in an aligned conditionsuitable for riding, and via a second detent in a pivotally displacedcondition suitable for storage. An example detent is a spring-biasedball detent unit 415 as illustrated in FIGS. 13A, B and C, but best seenby reference to FIGS. 13B and C, which depict the spring-biased balldetent unit 415 having an end support cap 417, a compression spring 419and a ball bearing 420 disposed substantially in the body of upperportion 295, with the ball bearing 420 being biased by the compressionspring 419 to engage with a detents 425 and 426 disposed at the outersurface of the first interlocking feature 310 of the lower portion 300.Detent 425 correlates with the first detent suitable for riding, anddetent 426 correlates with the second detent suitable for storage. Whiledetents 425, 426 are depicted as indentations in the outer surface offirst interlocking feature 310 for receiving the spring-loaded ballbearing 420, the detents may be of any geometry suitable for thepurposes disclosed herein, all of which are considered within the scopeof embodiments of the invention. In an embodiment, detents 425 and 426are displaced 160-degrees apart from each other (angle α, FIG. 13A), butmay be displaced at any angle suitable for the purposes disclosedherein.

In response to the interlocking features 305, 306 of the upper portion295 and the interlocking features 310, 311 of the lower portion 300being engaged with each other, and in response to the fastener 315fastening the upper portion 295 to the lower portion 300, the upper 295and lower 300 portions of the hinge 175 are prevented from having anyrelative movement between them. Also, in response to the fastener 315being loosened and not fastening the upper portion 295 to the lowerportion 300, the upper 295 and lower 300 portions of the hinge 175 areprevented from having rotational relative movement between them untilthe upper 295 and lower 300 portions are partially separated from eachother via translational relative movement between them. Furthermore, inresponse to the upper 295 and lower 300 portions being only partiallyseparated from each other, the first 305 of the interlocking features ofthe upper portion 295 and the first 310 of the interlocking features ofthe lower portion 300 remain engaged with each other and act as a pivot,and the second 306 of the interlocking features of the upper portion 295and the second 311 of the interlocking features of the lower portion 300are disengaged from each other thereby allowing the upper portion 295 topivot on the lower portion 300 about the pivot 325 defined by the pairof first interlocking features 305, 310. To fold and store the bicycle100, the upper and lower portions 295, 300 are partially separated asdiscussed above, and the frame sections 120, 125 pivoted relative toeach other via hinge 175 until the ball bearing 420 of the spring-biasedball detent unit 415 snaps into the detent 426 on the first interlockingfeature 310. To unfold the bicycle, manual pivoting of the framesections about the hinge is sufficient to drive the ball bearing 420 outof the detent 426 by compression of the spring 419. Continued unfoldingto align the front 120 and rear 125 sections results in spring-biasedball detent unit 415 snapping into detent 425. The spring-biased balldetent unit 415 engages and disengages in a similar manner with respectto the two detents 425, 426.

With brief reference back to FIGS. 1 and 3, another embodiment of theinvention disclosed herein includes a seat support 170 attached to thefront section 120 via a seat support clamp 340 that permits the seatsupport 170 to be disposed in a first position (as depicted in FIG. 1)suitable for riding, and in a second position (as depicted in FIG. 3)suitable for storing. Seat support clamp 340 may be arranged as apivotal member, or as a rigid member capable of providing theaforementioned two positions or enabling separation and removal of theseat support 170 from the front section 120.

In addition to all of the foregoing and with reference to FIG. 14,embodiments of the invention may include other features, such as thedrive link case 140 including supports 345 integrally arranged withlower tube 150 for mounting a disc brake caliper 350 on the underside oflower tube 150. Alternatively and with reference to FIG. 15, disc brakecaliper 350 may be mounted within the window 165 of drive link case 140by supports 355 disposed on the underside of upper tube 145 and on theupperside of lower tube 150.

FIGS. 16-18 illustrate an alternative structure for the frame 105(referred to in FIG. 16 by reference numeral 105′) as compared to thoseillustrated in FIGS. 1-3 and as discussed above. For example, FIGS.16-19 illustrate a single-sided bicycle frame structure with frontsection 120 (referred to in FIG. 16 by reference numeral 120′) having atriangular form 395 (as discussed above), in combination with a drivelink case 140 as discussed above, but absent a hinge 175.

FIG. 19 illustrates an alternative embodiment for the drive link case140 having two windows 360, 365 formed by a central tubular rib 370extending between the upper tube 145 and the lower tube 150 such thatthe above-described opening 165 is now defined by a first opening(window 360) and a second opening (window 365). In an embodiment,material forming the tubular rib 370 is continuous with material formingthe upper tube 145 and material forming the lower tube 150. Use of thecentral tubular rib 370 provides an additional structural feature toincrease the stiffness of the drive link case 140.

FIG. 20 illustrates an exemplary drive link 385, herein illustrated as abicycle chain, disposed around a front sprocket 390 for use inaccordance with embodiments described herein.

While certain combinations of features relating to a bicycle have beendescribed herein, it will be appreciated that these certain combinationsare for illustration purposes only and that any combination of any ofthese features may be employed, explicitly or equivalently, eitherindividually or in combination with any other of the features disclosedherein, in any combination, and all in accordance with an embodiment ofthe invention. Any and all such combinations are contemplated herein andare considered within the scope of the invention disclosed.

In view of all of the foregoing, it will be appreciated that embodimentsof the invention are well suited for implementation as an electric-driveor an electric-assisted-drive bicycle, where a battery and/or electricdrive mechanism may be disposed in any of the following locations: thewindow space between the tubes 275 of the first or second portions 280,285 of front section 120 (see FIG. 1); the window space 173 between theupper and lower tubes 171, 172 of seat support 170 (see FIG. 1); thespace below the seat support 170 and proximate the first portion 280 ofthe front section 120 (see FIG. 1); and, the window space defined by thetriangular form 395 of frame 105′ (see FIG. 16). Control and/or electricharness wires for such an electric-drive or electric-assisted-drivebicycle could run alongside or through any of the tubular frame sectionsdiscussed above, including passing through the axial through opening 330of rotatable joint 325 of hinge 175 (see FIG. 13). Any and all suchelectric-drive or electric-assisted-drive bicycles are contemplatedherein.

As disclosed, some embodiments of the invention may include some of thefollowing advantages: a structural single sided chain case with acentral window, absent a third leg (seat stay tube) extending from topof seat tube to end of chain stay tube typically found in triangularrear sections of bicycle frames; a structural single sided chain caseusable with a single speed or with a multi-gear hub; a structural singlesided chain case usable with a disc brake assembly; a structural singlesided chain case having an opening for receiving a hub gear shift cable;a structural single sided chain case having a removable torque transferrear cover for chain fit and adjustment; an eccentric crank for chaintension adjustment; an eccentric rotatable and removable crank cover forcrank installation and alignment with eccentric crank; a single sidedfoldable bicycle with a structural single sided chain case; a rotatablejoint for a single sided foldable bicycle having a through passage forgear and brake cables; a rotatable joint for a single sided foldablebicycle having a substantially vertical pivot axis thereby allowing thefront wheel to be folded against the rear wheel with the axlessubstantially aligned; a drive link case having a continuous flow ofmaterial among the various sections for an improved strength-to-weightand/or stiffness-to-weight ratio; a drive link case having a continuousflow of material among the various sections that eliminate localizedstress concentrations occurring at bolted joints such as those found inbolted clam shell type chain case designs.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best oronly mode contemplated for carrying out this invention, but that theinvention will include all embodiments falling within the scope of theappended claims. Also, in the drawings and the description, there havebeen disclosed exemplary embodiments of the invention and, althoughspecific terms may have been employed, they are unless otherwise statedused in a generic and descriptive sense only and not for purposes oflimitation, the scope of the invention therefore not being so limited.Moreover, the use of the terms first, second, etc. do not denote anyorder or importance, but rather the terms first, second, etc. are usedto distinguish one element from another. Furthermore, the use of theterms a, an, etc. do not denote a limitation of quantity, but ratherdenote the presence of at least one of the referenced item.

1. A bicycle frame configured to receive front and rear wheels, theframe comprising: a front section comprising a front frame portionhaving a front coupling configured and dimensioned to receive a frontwheel support member and to allow a rotational degree of freedom betweenthe front coupling and the front wheel support member, the front frameportion defining a central vertical plane of the frame; and a rearsection comprising a drive link case, the drive link case comprising anupper tube, a lower tube, a rear hub housing, and a front sprockethousing all integrally arranged with each other to form a rigid drivelink case having an opening disposed between the upper and lower tubes,the drive link case being connected to the front frame portion via thefront sprocket housing; the drive link case being disposed eccentric tothe central vertical plane and being cantilevered rearward from thefront sprocket housing, the front frame portion extending forward fromthe front sprocket housing.
 2. The bicycle frame of claim 1, wherein:the drive link case comprises one or more removable covers to provideaccess to the interior of the drive link case for removing and replacinga drive link, the drive link being defined by a bicycle drive chaindisposed in a loop traversing a path extending from the front sprockethousing, through the upper tube, around the interior of the rear hubhousing, through the lower tube, and returning to the front sprockethousing.
 3. The bicycle frame of claim 1, wherein: material forming theupper tube is non-separable along its respective length and around itsrespective circumference; material forming the lower tube isnon-separable along its respective length and around its respectivecircumference; material forming the rear hub housing is non-separablewith the material forming the upper tube and the material forming thelower tube; and material forming the front sprocket housing isnon-separable with the material forming the upper tube and the materialforming the lower tube.
 4. The bicycle frame of claim 1 wherein: thefront sprocket housing is closer to the central vertical plane than isthe rear hub housing thereby defining the drive link case to have anoffset shape.
 5. The bicycle frame of claim 1, wherein: at least one ofthe upper tube and the lower tube has a tubular cross section with eightsurfaces.
 6. The bicycle frame of claim 3, wherein: at least one of theupper tube and the lower tube has an overall cross-sectional height thatis greater that a respective overall cross-sectional width; and theupper and lower tubes are disposed non-parallel to each other.
 7. Thebicycle frame of claim 1, wherein the rear section is fixedly andimmovably connected to the front section.
 8. The bicycle frame of claim1, wherein the drive link case further comprises a tubular rib extendingbetween the upper tube and the lower tube such that the opening isdefined by a first opening and a second opening, material forming thetubular rib being non-separable with material forming the upper tube andmaterial forming the lower tube.
 9. The bicycle frame of claim 1,wherein: the front frame portion comprises a rigid substantiallytriangular form having a top frame member, a down frame member, and aseat frame member, the top frame member extending from the frontcoupling to an upper end of the seat frame member, and the down framemember extending from the top frame member at the front coupling to alower end of the seat frame member, thereby defining the rigidsubstantially triangular form; the drive link case being connected tothe front frame portion proximate the lower end of the seat framemember.
 10. The bicycle frame of claim 1, wherein: the front frameportion comprises two parallel tubes extending more upward than forwardfrom the front sprocket housing of the drive link case, thereby defininga first portion, and then extending more forward than upward toward thefront coupling, thereby defining a second portion.
 11. The bicycle frameof claim 10, further comprising: a frame hinge disposed in the firstportion such that: the front and rear wheels are lockable in line witheach other suitable for riding; at least a portion of the front sectionis pivotally displaceable with respect to the rear section such that thefront and rear wheels are not in line with each other; and, at least aportion of the front section and the rear section are positionallyfixable together via a detent in a pivotally displaced conditionsuitable for storage.
 12. The bicycle frame of claim 10, furthercomprising: a rotatable joint disposed in the first portion and having apivot axis in a near-vertical orientation, the rotatable jointcomprising a clamping mechanism that rigidly clamps the first portion inalignment with the second portion in the central vertical plane in amanner to make the bicycle frame suitable for riding.
 13. The bicycleframe of claim 12, further comprising: a seat support attached to thefront frame portion via a seat support clamp that permits the seatsupport to be disposed in a first position suitable for riding and in asecond position suitable for storing, the seat support comprising anupper support and a lower support with a opening disposed therebetween.14. The bicycle frame of claim 1, wherein: the drive link case ispivotally connected to the front frame portion about a frame axissubstantially normal to the central vertical plane of the frame, thedrive link case forming a swing arm to allow suspension between thefront frame portion and the drive link case; and further comprising: asuspension link disposed between the front frame portion and the drivelink case.
 15. The bicycle frame of claim 14, wherein the suspensionlink comprises a shock absorber.
 16. The bicycle frame of claim 14,wherein: the front frame portion comprises two parallel tubes extendingmore upward than forward from the front sprocket housing of the drivelink case, thereby defining a first portion, and then extending moreforward than upward toward the front coupling, thereby defining a secondportion; material forming the first portion is non-separable withmaterial forming the second portion.
 17. The bicycle frame of claim 14,wherein: the front frame portion comprises a rigid substantiallytriangular form having a top frame member, a down frame member, and aseat frame member, the top frame member extending from the frontcoupling to an upper end of the seat frame member, and the down framemember extending from the top frame member at the front coupling to alower end of the seat frame member, thereby defining the rigidsubstantially triangular form; the drive link case being connected tothe front frame portion proximate the lower end of the seat framemember.
 18. A drive link case for a bicycle frame, comprising: an uppertube, a lower tube, a rear hub housing, and a front sprocket housing allintegrally arranged with each other to form a rigid drive link casehaving an opening disposed between the upper and lower tubes; wherein:the upper and lower tubes are disposed non-parallel to each other; atleast one of the upper tube and the lower tube has a cross-sectionalheight that is greater than a respective cross-sectional width; materialforming the upper tube is non-separable along its respective length andaround its respective circumference; material forming the lower tube isnon-separable along its respective length and around its respectivecircumference; material forming the rear hub housing is non-separablewith the material forming the upper tube and the material forming thelower tube; and material forming the front sprocket housing isnon-separable with the material forming the upper tube and the materialforming the lower tube.
 19. The drive link case of claim 18, wherein: atleast one of the upper tube and the lower tube has a tubular crosssection with eight surfaces.
 20. The drive link case of claim 18,further comprising: a tubular rib extending between the upper tube andthe lower tube such that the opening is defined by a first opening and asecond opening, material forming the tubular rib being non-separablewith material forming the upper tube and material forming the lowertube.